158 lines
6.1 KiB
HTML
158 lines
6.1 KiB
HTML
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
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<!-- Copyright (c) 2001 The Open Group, All Rights Reserved -->
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<title>stdin</title>
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<basefont size="3"> <a name="stdin"></a> <a name="tag_03_718"></a><!-- stdin -->
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<!--header start-->
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<center><font size="2">The Open Group Base Specifications Issue 6<br>
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IEEE Std 1003.1-2001<br>
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Copyright © 2001 The IEEE and The Open Group, All Rights reserved.</font></center>
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<!--header end-->
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<hr size="2" noshade>
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<h4><a name="tag_03_718_01"></a>NAME</h4>
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<blockquote>stderr, stdin, stdout - standard I/O streams</blockquote>
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<h4><a name="tag_03_718_02"></a>SYNOPSIS</h4>
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<blockquote class="synopsis">
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<p><code><tt>#include <<a href="../basedefs/stdio.h.html">stdio.h</a>><br>
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<br>
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extern FILE *stderr, *stdin, *stdout;<br>
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</tt></code></p>
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</blockquote>
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<h4><a name="tag_03_718_03"></a>DESCRIPTION</h4>
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<blockquote>
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<div class="box"><sup>[<a href="javascript:open_code('CX')">CX</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]"
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border="0"> The functionality described on this reference page is aligned with the ISO C standard. Any conflict between the
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requirements described here and the ISO C standard is unintentional. This volume of IEEE Std 1003.1-2001 defers to
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the ISO C standard. <img src="../images/opt-end.gif" alt="[Option End]" border="0"></div>
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<p>A file with associated buffering is called a <i>stream</i> and is declared to be a pointer to a defined type <b>FILE</b>. The <a
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href="../functions/fopen.html"><i>fopen</i>()</a> function shall create certain descriptive data for a stream and return a pointer
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to designate the stream in all further transactions. Normally, there are three open streams with constant pointers declared in the
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<a href="../basedefs/stdio.h.html"><i><stdio.h></i></a> header and associated with the standard open files.</p>
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<p>At program start-up, three streams shall be predefined and need not be opened explicitly: <i>standard input</i> (for reading
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conventional input), <i>standard output</i> (for writing conventional output), and <i>standard error</i> (for writing diagnostic
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output). When opened, the standard error stream is not fully buffered; the standard input and standard output streams are fully
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buffered if and only if the stream can be determined not to refer to an interactive device.</p>
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<p><sup>[<a href="javascript:open_code('CX')">CX</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]" border="0"> The
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following symbolic values in <a href="../basedefs/unistd.h.html"><i><unistd.h></i></a> define the file descriptors that shall
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be associated with the C-language <i>stdin</i>, <i>stdout</i>, and <i>stderr</i> when the application is started:</p>
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<dl compact>
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<dt>STDIN_FILENO</dt>
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<dd>Standard input value, <i>stdin</i>. Its value is 0.</dd>
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<dt>STDOUT_FILENO</dt>
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<dd>Standard output value, <i>stdout</i>. Its value is 1.</dd>
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<dt>STDERR_FILENO</dt>
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<dd>Standard error value, <i>stderr</i>. Its value is 2.</dd>
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</dl>
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<p>The <i>stderr</i> stream is expected to be open for reading and writing. <img src="../images/opt-end.gif" alt="[Option End]"
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border="0"></p>
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</blockquote>
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<h4><a name="tag_03_718_04"></a>RETURN VALUE</h4>
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<blockquote>
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<p>None.</p>
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</blockquote>
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<h4><a name="tag_03_718_05"></a>ERRORS</h4>
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<blockquote>
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<p>No errors are defined.</p>
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</blockquote>
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<hr>
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<div class="box"><em>The following sections are informative.</em></div>
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<h4><a name="tag_03_718_06"></a>EXAMPLES</h4>
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<blockquote>
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<p>None.</p>
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</blockquote>
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<h4><a name="tag_03_718_07"></a>APPLICATION USAGE</h4>
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<blockquote>
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<p>None.</p>
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</blockquote>
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<h4><a name="tag_03_718_08"></a>RATIONALE</h4>
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<blockquote>
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<p>None.</p>
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</blockquote>
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<h4><a name="tag_03_718_09"></a>FUTURE DIRECTIONS</h4>
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<blockquote>
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<p>None.</p>
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</blockquote>
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<h4><a name="tag_03_718_10"></a>SEE ALSO</h4>
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<blockquote>
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<p><a href="fclose.html"><i>fclose</i>()</a> , <a href="feof.html"><i>feof</i>()</a> , <a href="ferror.html"><i>ferror</i>()</a> ,
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<a href="fileno.html"><i>fileno</i>()</a> , <a href="fopen.html"><i>fopen</i>()</a> , <a href="fread.html"><i>fread</i>()</a> , <a
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href="fseek.html"><i>fseek</i>()</a> , <a href="getc.html"><i>getc</i>()</a> , <a href="gets.html"><i>gets</i>()</a> , <a href=
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"popen.html"><i>popen</i>()</a> , <a href="printf.html"><i>printf</i>()</a> , <a href="putc.html"><i>putc</i>()</a> , <a href=
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"puts.html"><i>puts</i>()</a> , <a href="read.html"><i>read</i>()</a> , <a href="scanf.html"><i>scanf</i>()</a> , <a href=
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"setbuf.html"><i>setbuf</i>()</a> , <a href="setvbuf.html"><i>setvbuf</i>()</a> , <a href="tmpfile.html"><i>tmpfile</i>()</a> , <a
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href="ungetc.html"><i>ungetc</i>()</a> , <a href="vprintf.html"><i>vprintf</i>()</a> , the Base Definitions volume of
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IEEE Std 1003.1-2001, <a href="../basedefs/stdio.h.html"><i><stdio.h></i></a>, <a href=
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"../basedefs/unistd.h.html"><i><unistd.h></i></a></p>
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</blockquote>
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<h4><a name="tag_03_718_11"></a>CHANGE HISTORY</h4>
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<blockquote>
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<p>First released in Issue 1.</p>
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</blockquote>
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<h4><a name="tag_03_718_12"></a>Issue 6</h4>
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<blockquote>
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<p>Extensions beyond the ISO C standard are marked.</p>
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<p>A note that <i>stderr</i> is expected to be open for reading and writing is added to the DESCRIPTION.</p>
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</blockquote>
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<div class="box"><em>End of informative text.</em></div>
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